Coronary artery disease (CAD) is the principal basis of morbidity and mortality worldwide, and more than half of individuals experiencing acute myocardial infarction (AMI) have no premonitory symptoms. The prognosis for women with AMI is worse than for men, with higher case fatality rates and greater morbidity and mortality in the post-AMI period. Limited invasive and autopsy studies have identified gender-specific differences in coronary atherosclerotic plaque features at the time of presentation of AMI. To date, no study has examined (a) gender differences in atherosclerotic plaque characteristics (APCs) for individuals before AMI occurrence and (b) whether APC assessment can improve stratification of women and men who present with stable CAD but are at risk for future unheralded AMI. Coronary CT angiography (CT) is a non-invasive test that permits diagnosis of coronary stenosis with high diagnostic accuracy in women and men, as well as evaluation of atherosclerotic plaque and coronary arterial wall features. We have recently developed the prospective multicenter international CONFIRM observational cohort study of 32,308 carefully followed patients undergoing CT with comprehensive CAD risk factor, image finding, and CAD event ascertainment. We propose to use this rich resource to elucidate the gender-specific prognostic significance of coronary artery plaque characteristics beyond angiographic coronary stenosis for the non-invasive identification of coronary lesions that will be implicated in future AMI. The OVERALL HYPOTHESIS of the present proposal is that APCs quantified by CT will enhance gender- specific identification of coronary plaques that will cause future AMI. To examine this, we have assembled an unparalleled team of leading researchers in CAD, CT, women's health, outcomes research, and epidemiology. We describe a study protocol that is a logical and natural extension of our prior work with 3 specific aims: AIM 1: To identify the atherosclerotic features of coronary plaques that will be subsequently implicated in future AMI. AIM 2: To compare gender-specific differences in coronary plaques for women versus men who will subsequently experience future AMI. AIM 3: To determine the gender-specific risk of coronary atherosclerotic plaque characteristics that prognosticates AMI. If successful, the work in this proposal will provide the rationale for a novel diagnostic and potentially therapeutic paradigm that not only precisely identifies women and men who are at risk for future AMI, but also the gender-specific coronary lesions implicated as the cause.